Ink pad for duplicating machines



INVENTOR M LLI/1M EHT'H TTORNEY W1 F. HERTERICH INK PAD FOR DUPLICATINGMACHINES Filed OCb. 22, 1938 July 18, 1939.

Patented July 18, 1939 UNITED STATES PATENT OFFICE William F. Herterich,Brooklyn, N. Y., assignor to The Technygraph, Techny, Ill.

Application Gctober 22, 1938, Serial No. 236,434

7 Claims.

This invention relates to improvements in rotary stencil duplicatingmachines and more particularly to an improved ink pad and the manner ofits attachment to the duplicating machine.

The primary object of the present invention isto provide an improved inkpad for rotary stencil duplicating machines and to improve the method ofattaching the pad onto the machine.

A further object of the invention is to provide an improved ink padwhich is readily attachable and removable from the drum of theduplicating machine.

In accordance with the objects of the present invention, the improvedink pad comprises a sheet of suitable fabric such as cotton flannel ofthe desired size which is provided at one end with a springy yieldingattachment member and at the other end with an attachment means adaptedto apply the desired amount of stress or strain to the pad as it isfinally secured to the cylinder or drum of the duplicating machine. Theimprovements of the present invention particularly relate to machines ofthe type described in Brasseur Patent No. 1,607,386.

Other features and objects of the present invention will be apparent tothose skilled in the art from the following more detailed descriptionthereof taken in connection with the accompanying drawing in which:

Fig. 1 is an enlarged broken sectional View of a portion of the cylinderor drum of a stencil duplicating machine such as that shown in theabovementioned patent or those now commonly in use,

i showing the arrangement for attaching one end of the ink pad to therotary drum.

Fig. 2 is a view similar to that of Fig. 1 showing the manner ofattaching the other end of the ink pad to the rotary drum.

Fig. 3 is a broken front View (looking up in Fig. 1) showing the mannerof attaching one end of the pad to the cylinder as in Fig. 1.

Fig. 4 is a View similar to Fig. 3 (looking up in Fig. 2) showing theopposite end of the pad attached to the drum as in Fig. 2.

Fig. 5 is a broken perspective View of the improved ink pad of thepresent invention.

Fig. 6 is an enlarged View of one of the pivoting or leverage armscomprising a part of one end of the improved ink pad.

Rotary stencil duplicating machines now in use and shown in theabove-mentioned patent oomprise a cylinder or drum having end wallsconnected by a perforated diaphragm forming a substantial portion of theouter periphery of the drum. The remaining portion of the periphery ofthe drum is usually on a considerably smaller diameter so that space isprovided within the arc of the outer periphery for attaching the ink padand stencil sheet over the diaphragm and for other attachments andstructure.

In Figs. 1 and 3 is shown a broken section of the drum at the leadingend of the perforated diaphragm; one end plate of the drum being shownat 2 and the diaphragm at 4. The diaphragm 4 is attached to a crossplate 6 provided with spaced prongs 8 which are adapted to engage theattachment members of the leading end of the ink pad designated as I0,which is shown mounted on the diaphragm 4. This end attachment member ofthe pad comprises a heavy spring-steel rod or wire l2 of about 9 gaugeover which the fabric of the pad is secured, as shown in Figs. 1 and 3.The ends of the Wire member l2 are bent back as shown in Fig. 3 and madeinto flattened engagement members adapted to engage the prongs 8. Eachof these engagement members comprises a positioning point or thumb I4adapted to engage the side of the prongs 8, and an arced hook member I6adapted to pass around the back of the prong 8 to hold the pad on thedrum.

In attaching the leading end of the pad to the drum therefore, it willbe apparent that the only steps necessary are to place one of the pointsI4 against the corresponding prong 8, which will automatically positionthe opposite end and then merely pull the pad forward until the hooks I6engage the prongs 8.

The trailing end of the ink pad is constructed and applied to thecylinder in the manner shown in Figs. 2 and 4 in which the fabric of thepad I0 is shown stretched over the diaphragm 4, and the latter beingsupported on an inwardly extending plate i8 attached to thek edge of thediaphragm and the end plate 2. This portion of the drum or cylinder isprovided with a rod 2li which extends across the cylinder near thetrailing end of the diaphragm. The ends of the rod extend through slotsin blocks or casings 22. The ends of the rod 20 are attached to suitablemechanism 24 for moving the rod 20 toward or away from the center of thedrum. This mechanism is now in use on commercial machines and comprisesno part of the present invention except in general combination withattachment of the trailing end structure of the improved ink pad.

The trailing end structure of the ink pad comprises a spring-steel wireor rod 26 of approximately 9 gauge bent in the U-shape shown in Figs. 4and 5. The fabric of the pad is passed over the rod 26 and securedthereto in a manner similar to that of the opposite end of the pad. Eachof the ends of the wire 26 are bent back at right angles to provideextensions about an inch in length, flattened at their ends, and punchedto form a two-prong fork as shown in Figs. 2 and 6. This fork comprisesopposite prongs 28 cut so as to form an approximate semicircle adaptedto t over the rod 20.

The trailing end of the ink pad is attached to the machine (after theleading end) by first setting the prongs 28 of the wire 26 over the rod20 as shown in Fig. 4 and swinging the end of the pad into the positionshown in Fig. 2, so that the fabric of the pad is stretched over theedge of the diaphragm 4 and over the rod 20. The trailing end of the padis provided with openings 30 which expose the wire 26 at these points.As the trailing end of the rod is forced into place, it is held there bypivoted hooks 32 which engage the end of the pad over the wire 26 at thepoint of the openings 3D. With the use of certain types of hooks, theopenings 36 are entirely unnecessary,

because the hooks will retain the trailing end of the pad in positionbecause of the thickness and rounded character of the rod 26 in the endof the ink pad. The hooks 32 are pivoted as shown and preferablyprovided with springs not shown), to

, keep them in position over the end of the pad.

The U-shape of the wire 26 and the fact that its ends point toward theopposite end of the pad ill provide a toggle or leverage action forstretching the ink pad into position. As the ink pad is stretched intoposition any unevenness in stretching or other irregularity in thefabric will be taken care of by the resilience of the spring ends of thewire l2. These ends act independently of each other and materially aidin adjusting the fabric to the perforated diaphragm. Any materialvariation in the length of the pads used on a given machine may bereadily taken care of by varying the position of the rod 2B with respectto the edge of the diaphragm 4, by use of the mechanism 24 on either orboth ends of the rod.

The fabric of the pad is preferably attached to the wires l2 and 26, asshown in enlarged detail of Fig. 6 by lapping the fabric over the longstraight portions of each wire and lapping the 1 end section 34 of thefabric back along the main section of the fabric. This end section ispreferably vulcanized to the main section of the fabric by inserting astrip of rubber between the two sections adjacent to the wire andpressing the tWo sections of the fabric together while heating the same.This forms a very strong stiff bond. The ends are preferably finished bylacquering all of lthe lapped portion of the fabric 34 as well as thaton the opposite side and that over the Wires. On

2;, the trailing end of the pad the fabric is preferably lacquered for adistance sufficient that the portion of the pad on the end of thediaphragm is lacquered for at least one half inch (see Fig. 6). Thisprevents seepage of ink through the pad into the space beyond thediaphragm. Instead of using lacquer the fabric at this point may beimpregnated with an ink-resisting plastic such as a wax, to seal the endof the diaphragm. Any lacquer or plastic which will prevent the oilscontained in inks from attacking the vulcanized rubber are suitable forcoating the ends of the pad; for example a varnish or a celluloselacquer. A plastic may protect the rubber and seal the trailing end ofthe diaphragm. The wires I2 and 26 are preferably sealed (vulcanized) tothe fabric in the positions shown, so that the ends of the wire I2extend beyond the pad proper, while the ends of the wire 26 extend backalong the edges of the fabric.

Various modifications may be made in the improved ink pad and its mannerof attachment without departing from the spirit and scope of theinvention, and such changes are contemplated in accordance with thescope of the appended claims.

Having thus described the invention in its preferred form what isclaimed as new is:

l. In a rotary stencil duplicating machine, in combination a cylinderhaving a perforated diaphragm, an ink pad extending over said perforateddiaphragm and attached to said cylinder by end attachment members, oneof said end attachment members comprising a heavy wire to which thefabric of the ink pad is secured, the ends of said wire extending beyondthe end of the pad and being bent inwardly toward the opposite sides atan acute angle, a positioning point on the end of each wire end, and ahook also on each wire end adapted to engage corresponding prongs fixedto the cylinder.

2. In a rotary stencil duplicating machine, in

combination a cylinder having a perforated diaphragm and an ink padmounted on said diaphragm and attached to said cylinder by endattachment members, one of said attachment members comprising a wireover which the end of the fabric of the pad is secured, the ends of saidwire comprising arms extending at approximately right angles to theportion of the wire to which the fabric is attached, and a fork at theend of each arm, a rod secured to the cylinder at one end of thediaphragm over which the fabric of the pad is extended and cnto whichthe forks of said arms are placed, and means for retaining the end ofthe pad in position with the fabric and the arms bearing on the rod.

3. In a rotary stencil duplicating machine, in combination a cylinderhaving a perforated diaphragm, a rod at one end of the diaphragmextending crosswise of the cylinder, an ink pad on the diaphragm andattached to the cylinder, one end of said pad extending over said rodand attached to the cylinder by means of an arm at each side of the endof the pad, said arms extending back along the sides of the pad withtheir ends bearing on said rod, and hooks on the cylf inder for engagingand holding the end of the pad in position.

4. An ink pad for rotary stencil duplicating machines, comprising asheet of fabric, and an attachment member secured to one end of thefabric sheet, said member comprising a relatively long straight sectionof heavy wire over which the end of the sheet is secured and similarcontinuing relatively short sections of said wire bent inwardly at anacute angle on each side of the sheet, the ends of said short sectionsincluding a hook.

5. An ink pad as defined by claim 4 in which the opposite end of saidsheet is provided with an attachment member adapted to apply a tensionin the sheet and said short wire sections and comprising a U-shapedheavy wire in which the fabric of the sheet is secured to the centralportion and the arms are relatively short compared to the length of thecentral portion of the U-shaped wire.

6. An ink pad for rotary stencil duplicating machines, comprising asheet of fabric, and an attachment member secured to one end of thefabric sheet, said member comprising a relatively long straight sectionof heavy Wire over Which the end of the sheet is secured and similarcontinuing relatively short sections of said Wire bent at a right angleto said straight section, the extending ends of said short sectionsbeing forked so that the prongs of each fork are in a planeperpendicular to said long straight section of the Wlre.

'7. An ink pad as defined by claim 6 in which the fabric of the padadjacent said attachment member is impregnated with an ink-resistingcompound for a distance such that it extends onto the trailing end ofthe diaphragm of the duplicating machine which will thereby be sealedagainst leakage of ink past the end of the diaphragm.

WILLIAM F. HE'RTERICH.

